Abeer Ebraheem¹,Nadia M. Zaghloul²,Tamer M. El-Shehawy^{3                     1-BDS, Faculty of Dentistry, MansouraUniversity. 2- Associate Professor of Operative Dentistry, Faculty of Dentistry, Mansoura University 3- Lecturer of Operative Dentistry, Faculty of Dentistry, Mansoura University} Abstract: Objective:Theaim of this study was to evaluate the potential of fluoride varnish and casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) in remineralizing the bleached enamel surface using microhardness test. Materials and Methods:In this experimental study, thirty enamel samples of sound human permanent  maxillary central incisors were prepared. Microhardness (MH) of all specimens was measured at base line andafter bleaching with 40% hydrogen peroxide which was applied 3 times to the specimens. After completion of the bleaching process, MH of samples was measured and then enamel specimens were divided into three equal groups (n 10).Group A was subjected to daily application of (CPP-ACP) (GC tooth mousse) paste for 15 days. Group B, the specimens were subjected to fluoride varnish (Bi fluoride 10) once every week for two weeks.  In group C, the specimens were stored in the artificial saliva at room temperaturefor 15 days. Final MH of all groups was measured. The data were analyzed using two way measures ANOVA (α = 0.05). Results:There was a significant decrease in microhardness of enamel in all groups. However, there was a significant increase in microhardness after the remineralization by fluoride, CPP-ACP and artificial saliva, the extent of remineralization is more for the Group of CPP-ACP. Conclusions:Bleaching agent reduced enamel microhardness and the use of either fluoride, CPP-ACPor artificial saliva after bleaching can significantly enhance the microhardness of bleached enamel. KEY WORDS:CPP-ACP, fluoride, bleaching, microhardness, remineralization